[web] Move onChangeAccountPassword up from ThreadSettingsModal to ConnectedThreadSettingsModal

Summary:
Move onChangeAccountPassword out from inner class component to outer "Connected" functional component.

As part of the work to refactor ThreadSettingsModal... specifically to turn it into a functional component.

Depends on D3768

Test Plan:

1. Open ThreadSettingsModal
2. Change account password under delete tab
3. Log values in onChangeAccountPassword to ensure that the state continues to change as expected

Reviewers: def-au1t, palys-swm

Reviewed By: palys-swm

Subscribers: ashoat, Adrian, karol-bisztyga, benschac, yayabosh

Differential Revision: https://phabricator.ashoat.com/D3769